Assistant Professor

**Room number:** ECOT 231

I joined the department of Applied Math in fall 2014. Previously I was a Herman Goldstine Postdoctoral fellow in Mathematical Sciences at IBM Research in Yorktown Heights, NY, and a postdoctoral fellow via the Fondation Sciences Mathématiques de Paris at Paris 6 (JLL lab), after doing my doctoral work at Caltech.

Broadly speaking, our group is interested in *information extraction* from various types of datasets. We are part of a hybrid field combining applied math with computer science and signal processing techniques. Some specific topics we research are:

- Optimization: first-order methods, quasi-Newton methods, primal-dual algorithms, convex analysis.
- Types of problems: from computational imaging, and semi-definite programs (from relaxations, or from robust PCA)
- Mathematical applications: compressed sensing and variants, matrix completion and variants (robust PCA…), non-negative matrix factorization and end-member detection, sparse SVM

- Numerical linear algebra: randomization and its interplay with optimization methods
- Sampling theory: how to make the best use of your resources when confronted with big data
- e.g., time-data tradeoffs
- e.g., sketching

- Physical applications: radar ADC using compressed sensing, quantum tomography, MRI, medical imaging, IMRT, renewable energy, big-data
- Recent applications (2015--2018) have been in super-resolution (optical) microscopy and photo-acoustic microscopy

To get a more specific idea of the research our group does, here are some topics we're doing in 2018:

- Parametric and compressive estimation, for phase retrieval (Jessica) in x-ray imaging, and for discovering archaeological ruins (Abby) in radar imaging without creating a DEM
- Theoretical machine learning: sub-sampling and sketching (Farhad, Eric)
- Avoiding/analyzing saddle points in non-convex optimization: for biconvex programming in program analysis and/or controls (Jessica), and for dictionary learning and neural network learning (Leo)
- Improving accuracy of sparse estimation using mixed-integer programming (Eric, Leo)
- Efficient computation of the cross-ambiguity function (CAF) for signal processing, to estimate time-of-arrival of radar signals (James)
- Randomized algorithms for numerical linear algebra and optimization (James, Derek)
- Optimization algorithms in general, and ill-conditioning and pre-conditioning (James, Jessica, Osman)
- Efficient algorithms for GPUs (James, Derek, Jessica)
- Tensor decompositions (Osman, Derek)
- Robust estimation (Richie)
- Misc imaging applications (for optical super-resolution, with Carol Cogswell's group in ECEE; and for photo-acoustic super-resolution, with Todd Murray's group in Mech E)
- Stochastic variance reduction methods for non-linear inverse problems
- Remote sensing of the Chesapeake bay (Cheryl)
- Behavior genetics (Richard, Farhad)

- July 2018: Becker is PI on a 3-year $150k NSF grant in computational math
- July 2018: Becker is Co-PI on Prof. Ken Jansen's ALCF project
- This gives us early access to the new Aurora supercomputer (the nation's first exascale computer)

- Summer 2018 activities:
- Will Shand is a new undergrad researcher in our group
- Zhishen (Leo) Huang is interning with Kristina Lerman's group at the Information Sciences Institute at USC
- Eric Kightley is interning with Respond Software
- Jessica Gronski is interning with SavvySherpa
- Stephen Becker is giving a two week short-course on optimization at Cambridge University in the UK (course notes) in June, then attending ISMP in Bordeaux France in July
- Osman Malik is attending COLT and ICML in Stockholm, Sweden in July

- Spring 2018: Farhad Pourkamali-Anaraki (PhD then Postdoc in the group) accepts a tenure-track professor job at U Mass Lowell's computer science deparment
- May 2017: Farhad Pourkamali-Anaraki receives his PhD in electrical engineering
- May 2017: Derek Driggs receives his Masters in applied math, and heads to Cambridge for his PhD
- April 2017: Derek Driggs wins the Gates Cambridge scholarship (fully funded PhD at Cambridge, equivalent to a Rhodes scholar for Oxford)
- Summer 2016:
- Farhad interns with Technicolor research
- Jessica interns with Tamara Kolda at Sandia
- James interns with ICR

- July 2015, Becker awarded the Beal-Orchard-Hays prize
- along with Michael Grant and Emmanuel Candes. The BOH prize is awarded every 3 years for outstanding optimization software

Our research group website has more information on research topics.

(note: there is also some interesting description of our work at our old website. The only website that we update regularly is the research group website)

January 2018, I am one of four founding members of the new Imaging Science center in the engineering college. Here is the new Imaging Science IRT website.

You may be interested in joining the Colorado data science team.

We run a Statistics, Optimization and Machine Learning seminar (Fall 2018, this is usually 3:30 Tuesdays at Newton lab). Anyone is welcome to show up.

(to receive announcements about talks at the seminar, please sign up for the StatOptML google group).

Some resources:

- The week-long summer STEM camp I am involved with (in collaboration with Northrop Grumman, St. Vrain School District, Rangeview HS, and Aurora Public Schools). 2017 in Aurora, and 2018 in Aurora and Longmont
- any Colorado high schooler can sign up to take the camps
- Applied Math graduate students help me teach the class

- NCWIT Aspirations in Computing (AiC), a non-profit at CU
- BOLD center (part of the engineering college; "Broadening Opportunity through Leadership and Diversity")
- ITLL Integrated Teaching and Learning Lab (part of the engineering college, located next to the engineering building)
- Idea Forge maker space and more
- Science Discovery
- CU wizards
- many more at the Center for STEM Learning's list of programs.

- CU Boulder is a top-25 research university with excellent resources
- According to NSF data, CU is #13 nationwide in total federal obligations, #7 nationwide by number of full-time graduate students in science, engineering, and health, and if you combine with our medical school, we are #20 nationwide in total R&D expenditures (other top-10 schools in R&D, like Duke, are already combined with their medical schools).
- CU is ranked the #2 university in the world for geosciences by the US News and World Report
- (2018 update: CU is now #1 in the world for geoscience and #43 overall in the world)
- #11 internationally in computer science by normalized citation index, #35 overall internationally in physics, etc.

- From the aerospace department website, CU is the #1 public university for NASA research funds, Colorado is the 2nd largest aerospace economy in the US, and our aerospace program is ranked #8 (graduate) and #10 (undergraduate)
- Earth and Atmospheric science is ranked #1 globally in 2018

- A unique feature of CU is the strength of our 11 institutes (ATLAS, Biofrontiers, CIRES, INSTAAR, IBS, ICS, JILA, LASP, ... ), as well as the nearby national labs (NOAA, NIST, NCAR)
- Applied Math is at the center of quantitative work in the institutes, as well as new statistical efforts on campus
- We are one of just a handful of specialized Applied Math departments in the US. An applied math degree greatly distinguishes graduates
- Ready to apply? Please apply to our department (we do not do direct admission into a research group)